Fast Surface Restructuring within the Gap of Au Nanocube Dimer for the Enhancement of Catalytic Efficiency

Abstract

Identification of the catalytic dynamics and plasmonic effects plays a critical role in the design of heterogeneous catalysts. However, the knowledge of plasmonic effect on catalytic dynamics remains limited at the single-particle level. Using the non-fluorescent amplex red to fluorescent resorufin as a model reaction, significant enhancement in catalytic efficiency from the coupled Au nanocube dimer (AuCD) was clearly revealedwith the single-molecule fluorescence microscopy. AuCD exhibits noticeably higher catalytic efficiency than the monomer, which is attributed to the spontaneous dynamic surface restructuring. Spatiotemporally resolved dynamics suggest that the active catalytic sites essentially originate from the plasmonic nanogap where an electromagnetic (EM) hot spot exists. The enhanced EMfield accelerates the generation of hot carriers and promotes the spontaneous surface restructuring by enhancing the lattice vibrations, which ultimately improves the catalytic activity. These microscopic views provide new insights into the effect of EM fields on surface restructuring dynamics of nanocatalysts.